Amid reports that North Korea is testing nuclear missiles, airlines are rerouting flight paths to avoid North Korean airspace.

Singapore Airlines announced this week that they have rerouted a flight from Seoul to Los Angeles. The airline changed the route back in July after a previous North Korean missile test, according to CNN Money. The new flight route goes further north to avoid the Sea of Japan.

On November 29th the crew of @cathaypacific flight CX893 from San Francisco to Hong Kong witnessed what they believed was a North Korean ballistic missile re-entering the Earth’s atmosphere… Here’s the Flight playback 👍🏼

The UN’s International Civil Aviation Organization states that nations have a “responsibility to issue risk advisories regarding any threats to the safety of civilian aircraft operating in their airspace.” However, South Korea says that the North Korean government regularly fails to issue these notices when conducting missile launches.

Federal regulation from 1997 prohibits all U.S. airlines from flying over the Flight Information Region of Pyongyang. Aircraft can fly into the capital with permission from the U.S. government or Federal Aviation Administration.

Travelers who are concerned should know the chances of an airplane colliding with a missile are extremely low: One safety analyst estimates that it is less than a billion to one.